Rotary screen printer with programmable screen interrupt

ABSTRACT

A rotary screen printing machine has a plurality of individual rotary screens each having a lifting device. A control element is connected to each of the lifting devices. A drive is operatively connected to the control element to synchronize the rate of rotation of each of the rotary screens and the lifting thereof by the lifting devices.

United States Patent [191 Zimmer [451 Sept. 10, 1974 1 ROTARY SCREEN PRINTER WITH PROGRAMMABLE SCREEN INTERRUPT [76] Inventor: Peter Zimmer, Untere Sparchen 54,

A-6330 Kufstein, Austriav 22 Filed: Sept. 5, 1972 21 Appl. No.: 286,304

[30] Foreign Application Priority Data Sept. 6, 1971 Austria 7721/71 [52] US. Cl ..101/115,101/116,101/127.1, 101/182 [51] Int. Cl B411 15/10 [58] Field of Search 101/116, 126, 127.1, 124, 101/283, 285, 284, 182, 184, 185, 123, 124,

[56] References Cited UNITED STATES PATENTS 1,840,073 1/1932 Williams 101/123 2,301,379 11/1942 Davis 101/248 2,893,310 7/1959 Johnson 101/182 2,925,036 2/1960 Crawford 101/182 3,139,025 6/1964 Chambon 101/182 X 3,304,862 2/1967 Lawrence et a1. 101/182 X 3,456,584 7/1969 Moskowitz 101/119 3,541,953 11/1970 Rochford 101/92 3,552,213 1/1971 Jeschke 101/247 X 3,774,533 11/1973 lchinose 101/119 3,774,534 11/1973 Ichinose 101/119 FOREIGN PATENTS OR APPLICATIONS 2,054,570 5/1971 Germany 101/116 Primary Examiner--Robert E. Pulfrey Assistant Examiner--R. E. Suter Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [57] ABSTRACT A rotary screen printing machine has a plurality of individual rotary screens each having a lifting device. A control element is connected to each of the lifting devices. A drive is operatively connected to the control element to synchronize the rate of rotation of each of the rotary screens and the lifting thereof by the lifting devices.

6 Claims, 5 Drawing Figures ROTARY SCREEN PRINTER WITH PROGRAMMABLE scREEN INTERRUPT BACKGROUND OF THE INVENTION This invention relates to a rotary screen printing machine having at least two screen printing devices the individual rotary screens of which are lifted to temporarily interrupt the printing process.

Temporary lifting of rotary screens in rotary screen printing machines is known hitherto wherein rotary screens have been produced by rolling up flat screens in order to form a circular cylinder. By the lifting process the joint area unsuitable for printing has been brought out of contact with the sheet of material.

SUMMARY OF THE INVENTION The object of the present invention is to provide a device enabling an alternate lifting and lowering of rotary screens when printing designs having patterns which are of relatively long overall length, such patterns being repeated by the rotary screens. Hereinafter, the length of the overall repeated pattern will be referred to as the long repeat distance. The long repeat distance of the overall repeated pattern may be distributed over the circumferences of several rotary screens and, with multicolor printing, the individual rotary screens or groups of rotary screens may be brought into contact, according to the design, with the surface to be printed for the purpose of printing the overall repeated pattern.

According to the invention this is achieved by the provision of a drive for the lifting devices of the individual rotary screen devices controlled by at least one drive shaft extending in the longitudinal direction of the machine, i.e. the direction of movement of the material. The lifting devices may be devices known per se, e.g. crank gears, eccentrics, cam plates, or the like.

Thus it is rendered possible to adjust the lifting movements of the different rotary screens or groups of rotary screens to the requirements of different designs, i.e. to the length and number of the shorter portions of the overall repeated pattern which are printed by the different rotary screens or groups of rotary screens.

The present invention is hereinafter described in detail with reference to the diagrammatic drawings annexed thereto without, however, being limited to these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an arrangement of the device according to the invention on a rotary screen printing machine,

, FIG. 2 shows the lifting device of two screen devices,

FIGS. 3a and 3b are screens with their gear drives in the lowered and lifted condition,

FIG. 4 shows the lifting device on a screen device with an adjustment for the height of lift.

DETAILED DESCRIPTION OF THE INVENTION Rotary screens 1 of a plurality of printing devices in FIG. 1 are fixed to rotate in screen supports 2, which are designed to be lifted and lowered-with respect to the material to be printed. During the printing process the sheet of material 3 runs over a printers blanket in direction 4 through the printing machine and at the point 5 disconnects from the printers blanket and passes into a drier, not shown in the drawings. Rotary screens 1 rotate in direction 6 during the passage of the sheet of material. Rotary screens 1 are driven, as known per se, and their circumferential speed is kep synchronous with the speed of the sheet of material. This is accomplished by a rotary motion imparted to the shaft 8 from the front guide roller 7 (not driven) and is then supplied to the individual transmission devices 9. The drive of the rear guide roller 10 is effected by motor 30. The shaft 8 extends substantially through the total longitudinal length of the machine and joins a transmission 11 in order to rotate a driveshaft 12. In order that rotary screens with different diameters and therewith different circumferences may be mounted on the printing machine and that the drive shaft 12 should make one revolution for each screen revolution, the capability exists in transmission 11 to bring about the necessary ratio of rate of revolutions by choosing any desired gear ratio of gears 13 of transmission 11. Furthermore there is a stepping mechanism 14 advantageously connected with drive shaft 12', which stepping mechanism receives one impulse for every revolution of drive shaft 12 and thereby transports a carrier of a predetermined program e.g'. a punched card or a perforated tape. Such card or tape is thus moved step-by-step and closes and opens electrical circuits in a predetermined sequence. Electrical impulses from these electrical circuits are thus supplied, in such predetermined sequence dependent on the program on the card or tape to control elements such as shifting couplings 15 illustrated in FIG. 2, by means of the supply mains 16. The different shifting couplings l5, e.g. electromagnetic clutches, thus selectively are closed or opened with each rotation of drive shaft-12. Each coupling 15 may remain open during one or more rotations of the drive shaft 12 or may remain closed during one or more rotations of drive shaft 12. There are bevel gears 17 carrying marks 18 on the drive shaft. Bevel gears 17 are adjustable in their rotary position relative to drive shaft 12. A ring 19 carries a zero mark 20 and is immovably connected with drive shaft 12. Bevel gear 17 mates with a corresponding bevel gear 21 mounted on the shaft of shifting couplings 15. If shifting coupling 15 receives a closing impulse, the rotary motion of the drive shaft 12 is imparted to the pair of bevel gears 23 by means of shaft 22, and a crank arm 25 lifts the screen support 2 with the rotary screen by means of crossbar 26 and rams 27. Rotary screen 1 thus may be lifted from the sheet of material 3 to be printed and the sheet of material then is not printed with the corresponding design in this area. Shifting coupling 15, the gear on drive shaft 12, gear 21, shaft 22 and gears 23 form a coupling device means for transducing rotary movement of drive shaft 12 into lifting movement of the lifting device.

FIGS. 3a and 3b illustrate two difi'erent lifting steps of a rotary screen. The same reference numerals are valid as in the preceding figures. Rotary screen 1 is tightly connected with a gear 28 and mates with a corresponding gear, i.e. a drive wheel 29 associated with transmission device 9 and which causes screen 1 to rotate with the same circumferential speed as the other screens. While in FIG. 3a rotary screen 1 is in contact with the sheet of material 3, FIG. 3b illustrates a lifted condition, there being a distance 37 between rotary screen 1 and sheet of material 3. It is useful to keep distance 37 smaller than the depth of teeth of the two gears 28, 29, so that engagement of the gears is ensured even in the fully lifted condition. The rotary motion of the rotary screen 1 thereby is not interrupted upon lifting, although no immediate contact exists then with the sheet of material 3.

The adjusting device in FIG. 4 enables adjusting of the length of lift of the screen devices and therewith also of the area in which the printing process of a rotary screen is interrupted on the sheet of material 3. Adjusting screws 33 are provided for this purpose by means of which rams 27 may be shortened or extended. If the lifting device works by closing shifting couplings l5, crank arm 25 is put into motion, which crank arm lifts the two rams 27 in the sliding tubes 36 by means of crosspiece 26 until adjusting screws 33 are in contact with screen support 2. From this moment screen support 2 with the rotary screen positioned therein participates in the lifting movement, whereby the printing process is interrupted. Thus, the device of FIG. 4 may be employed to control the amount of lift of arm 25 before causing an accompanying actual lift of the screen. This is advantageous in precisely controlling the timing of raising and lowering of the screen.

What I claim is:

l. A rotary screen printing machine comprising:

a frame means for supporting material to be printed;

at least two printing devices supported on said frame means for printing said material, each of said printing devices including a rotary cylinder screen;

means for moving said material over said frame means to be sequentially contacted and printed by the rotary screens of each of said printing devices;

driving means driven by said means for moving for rotating the rotary screens of each of said printing devices at the same speed;

lifting device means connected to each of said printing devices for lifting said rotary screens thereof out of contact with said material;

a single drive shaft mounted on said frame means and extending therealong in the direction of movement of said material;

transmission means interconnected between said driving means and said drive shaft to impart rotation to said drive shaft;

a separate selectively operable coupling device means positioned between each of said lifting device means and said drive shaft for transducing rotary movement of said drive shaft into lifting movement of said lifting device means, each of said coupling device means having an operative position connecting the respective lifting device means with said drive shaft and an inoperative position interrupting such connection; and

means operable by the rotary movement of said drive shaft and connected to each of said coupling device means for selectively moving each of said coupling device means into and out of said operative positions thereof at predetermined times.

2. A machine as claimed in claim 1, wherein said transmission means rotates said drive shaft through one revolution thereof for each revolution of said rotary screens.

3. A machine as claimed in claim 1, wherein said lifting device means each comprise a screen support means supporting the rotary screen of the respective printing device and a crank arm connected to said screen support means and to the respective coupling device means.

4. A machine as claimed in claim 3, wherein each of said coupling device means comprises a shifting coupling; first gear means positioned on said drive shaft; second gear means operatively attached to said shifting coupling and in meshing engagement with said first gear means; third gear means operatively attached to said shifting coupling; and fourth gear means carrying said crank arm and in meshing engagement with said third gear means.

5. A machine as claimed in claim 3, wherein each of said coupling device means comprises a shifting coupling, and said means for selectively moving each of said coupling device means comprises a stepping mechanism and a carrier of a predetermined program, said carrier being stepped by said stepping mechanism at equal intervals dependent upon the angle of rotation of said drive shaft, said stepping mechanism delivering electrical impulses to each of said shifting couplings in a sequence dependent on said predetermined program and the stepped position of said carrier.

6. A machine as claimed in claim 1, wherein said driving means maintains rotation of said rotary screens when said rotary screens are in the lifted position. 

1. A rotary screen printing machine comprising: a frame means for supporting material to be printed; at least two printing devices supported on said frame means for printing said material, each of said printing devices including a rotary cylinder screen; means for moving said material over said frame means to be sequentially contacted and printed by the rotary screens of each of said printing devices; driving means driven by said means for moving for rotating the rotary screens of each of said printing devices at the same speed; lifting device means connected to each of said printing devices for lifting said rotary screens thereof out of contact with said material; a single drive shaft mounted on said frame means and extending therealong in the direction of movement of said material; transmission means interconnected between said driving means and said drive shaft to impart rotation to said drive shaft; a separate selectively operable coupling device means positioned between each of said lifting device means and said drive shaft for transducing rotary movement of said drive shaft into lifting movement of said lifting device means, each of said coupling device means having an operative position connecting the respective lifting device means with said drive shaft and an inoperative position interrupting such connection; and means operable by the rotary movement of said drive shaft and connected to each of said coupling device means for selectively moving each of said coupling device means into and out of said operative positions thereof at predetermined times.
 2. A machine as claimed in claim 1, wherein said transmission means rotates said drive shaft through one revolution thereof for each revolution of said rotary screens.
 3. A machine as claimed in claim 1, wherein said lifting device means each comprise a screen support means supporting the rotary screen of the respective printing device and a crank arm connected to said screen support means and to the respective coupling device means.
 4. A machine as claimed in claim 3, wherein each of said coupling device means comprises a shifting coupling; first gear means positioned on said drive shaft; second gear means operatively attached to said shifting coupling and in meshing engagement with said first gear means; third gear means operatively attached to said shifting coupling; and fourth gear means carrying said crank arm and in meshing engagement with said third gear means.
 5. A machine as claimed in claim 3, wherein each of said coupling device means comprises a shifting coupling, and said means for selectively moving each of said coupling device means comprises a stepping mechanism and a carrier of a predetermined program, said carrier being stepped by said stepping mechanism at equal intervals dependent upon the angle of rotation of said drivE shaft, said stepping mechanism delivering electrical impulses to each of said shifting couplings in a sequence dependent on said predetermined program and the stepped position of said carrier.
 6. A machine as claimed in claim 1, wherein said driving means maintains rotation of said rotary screens when said rotary screens are in the lifted position. 